Pool salt calculator for salt water pools
This pool salt calculator works out how much salt a salt water pool needs to go from its current salt level to the target. One ppm is one milligram per liter, so 20,000 gallons raised from 0 to 3200 ppm need about 534 lb of salt – fourteen 40-lb bags. Hayward names 2700–3400 ppm as the ideal range for its AquaRite chlorinators, with 3200 ppm as the optimum.
Example: Units: US gallons and pounds · Pool volume 20,000 · Current salt level 0 ppm · Target salt level 3,200 ppm · Bag size 40 → Salt to add: 534.1 lb of salt (14 bags of 40 lb). Source: Hayward – AquaRite Electronic Chlorine Generator, Owner’s Manual 092538 Rev D (salt level 2700–3400 ppm, chart “Pounds and (Kg) of salt needed for 3200 ppm”; read 09.10.2026). Updated: .
How it is calculated
Salt = water volume × (target ppm − current ppm). One ppm (part per million) is one milligram of salt per liter, or one gram per cubic meter. 1 m³ needs 1 kg of salt for every 1000 ppm, a US gallon weighs about 8.34 lb.
Pool salt chart (target 3200 ppm)
| Pool size | From 0 ppm | From 2000 ppm |
|---|---|---|
| 10,000 gal (37.9 m³) | 267 lb (121 kg) | 100 lb (45 kg) |
| 20,000 gal (75.7 m³) | 534 lb (242 kg) | 200 lb (91 kg) |
| 40,000 gal (151.4 m³) | 1068 lb (485 kg) | 401 lb (182 kg) |
Hayward’s AquaRite manual prints the same chart in steps of 200 ppm and 2000 gallons. It rounds slightly lower (533 lb instead of 534 lb for 20,000 gallons); the difference is below 0.3 %. The ideal range for AquaRite is 2700–3400 ppm. Below 2700 ppm the cell produces less chlorine; above it may shut down, and many people taste salt from about 3500–4000 ppm.
Examples
- New pool, 20,000 gallons, 0 → 3200 ppm: 534.1 lb of salt, fourteen 40-lb bags.
- 10,000 gallons at 2000 ppm: 100.1 lb to reach 3200 ppm.
- 50 m³, 0 → 3200 ppm: 160 kg, seven 25-kg bags.
- 4000 ppm measured, target 3200 ppm: salt cannot be taken out – replace 20 % of the water with fresh water.
Don’t know your volume? The pool volume calculator works it out from length, width and depth. Chlorine dosing for pools without a salt cell is covered by the pool chlorine calculator.
How to add the salt
Hayward recommends pure sodium chloride (over 99 %) – common food-quality salt, water softener salt or coarse “solar salt”; pellets also work but dissolve more slowly. Run the pump, spread the salt in the pool and brush it so it does not pile up on the bottom; let the pump run for 24 hours. In new plaster pools wait 10–14 days before adding salt. Salt is not lost by evaporation, only by splashing, backwashing or rain overflow.
Frequently asked questions
How much salt do I need for a 20,000-gallon pool?
From 0 to 3200 ppm about 534 lb (242 kg) – fourteen 40-lb bags. Hayward’s chart gives 533 lb.
How many bags of salt per 1,000 gallons?
About 26.7 lb per 1,000 gallons to go from 0 to 3200 ppm – two 40-lb bags cover about 3,000 gallons.
What should the salt level be in a salt water pool?
Hayward gives 2700–3400 ppm for its AquaRite cells, with 3200 ppm as the optimum. Other makers name their own range – check your manual.
How much does 40 lb of salt raise the ppm?
In 10,000 gallons, 40 lb raises the salt level by about 479 ppm; in 20,000 gallons by about 240 ppm.
What if the salt level is too high?
Salt cannot be removed with chemicals. Drain part of the water and refill: from 4000 to 3200 ppm replace about 20 %.
Which salt can I use?
Sodium chloride over 99 % pure – no rock salt, no salt with yellow prussiate of soda or anti-caking agents, no iodized salt.
Sources and legal basis
As of: · Editorial policy
Related tools
- Pool Volume Calculator – How Many Gallons Is My Pool?Pool volume calculator for rectangular, round, oval and kidney pools: enter size and depth, see gallons and liters – plus fill time and pump turnover time.
- Water Hardness ConverterWater hardness converter between °dH, mmol/l, °fH, °e, gpg and ppm (mg/l CaCO₃), with the hardness class from soft to very hard. Free, no sign-up.
- Electricity cost calculator for appliancesWork out what an appliance costs to run: enter watts, hours per day, days per week and your rate per kWh to get kWh and cost per day, month and year.
- Mass Percent CalculatorMass percent calculator: mass fraction from solute and solvent mass, the solute mass needed, ppm, per mille and a mixing cross for two solutions, with values.
- kg to lbs converterConvert kg to lbs and back: 1 kg = 2.2046 lb. Shows pounds and ounces, stone and pounds, grams, tons and a kg to lbs chart – exact to the legal definition.
- Fahrenheit to kelvin and kelvin to Fahrenheit converterFahrenheit to kelvin: add 459.67, multiply by 5/9, so 68 °F = 293.15 K. Type °F for kelvin, °C and Rankine, or go back from K to °F, with a chart and working.
- Minutes to seconds and seconds to minutes converterMinutes to seconds: multiply by 60, so 2.5 min = 150 s. Type minutes for seconds and the m:ss form, or seconds for minutes, plus the decimal trap.
- oz to liters and liters to oz converteroz to liters: 1 US fl oz = 0.0295735 L, so 64 oz = 1.8927 L. Type fluid ounces for liters (US or UK ounces), or liters for ounces, with a bottle-size chart.
- Knitting increase calculatorKnitting increase calculator: spread increases or decreases evenly across a round or row and get the written pattern, e.g. 60 stitches plus 10 increases.